Year	% gross
1970	5.07714986801147
1971	5.03642988204956
1972	4.99410009384155
1973	5.03422021865845
1974	5.17908000946045
1975	5.97348022460938
1976	7.39889001846313
1977	8.25594997406006
1978	8.28999996185303
1979	8.7680196762085
1980	8.76506996154785
1981	8.4738597869873
1982	8.95915031433105
1983	8.91543006896973
1984	9.49592018127441
1985	8.51072978973389
1986	8.82635974884033
1987	9.05370998382568
1988	8.92096042633057
1989	9.47659969329834
1990	9.77795028686523
1991	10.0741100311279
1992	10.1592502593994
1993	9.76478004455566
1994	9.70578002929688
1995	10.0311603546143
1996	10.6257495880127
1997	11.2199697494507
1998	12.2156896591187
1999	12.005220413208
2000	12.9872903823853
2001	13.5096998214722
2002	14.2689304351807
2003	15.2383098602295
2004	16.1802997589111
2005	17.5579891204834
2006	20.1768798828125
2007	20.3449897766113
2008	21.3638706207275
2009	23.495189666748
2010	24.1933403015137
2011	24.094539642334
2012	23.7807197570801
2013	23.6547393798828
2014	26.5228900909424
2015	27.3103694915771
2016	27.5193996429443
2017	28.4034595489502
2018	28.9170093536377
2019	30.2173805236816
2020	30.7744998931885